Device for expelling mercury and the like from amalgam



28, 1956 J. w. RICHARDS ETAL 2,760,268

DEVICE FOR EXPELLING MERCURY AND THE LIKE FROM AMALGAM Filed Aug. 51,1955 INVENTO am di CZeZZa/z United States Patent DEVICE FOR EXIELLINGlVlERCURY AND THE LIKE FROM AMALGAM John W. Richards and Wayne L.McClellan, Ottumwa, Iowa Application August 31, 1953, Serial No. 377,532

14 Claims. (Cl. 32-40) This invention relates to a dental tool orappliance useful in the expelling of mercury and the like from amalgamfor preparing so-called silver fillings.

Silver amalgam as used in the dental profession is composed of mercuryand silver alloy. These two materials are amalgamated by means of atriturating action through the use of high-speed vibration or by meansof hand trituration with a mortar and pestle. Silver alloy is an inertpowdered mass until amalgamated with mercury. This amalgamation producesa plastic mass in which the mercury serves as a catalytic agent. Afterthe mercury has served its catalytic function it must be expelled fromthe amalgam before the necessary crystallization can occur. The moremercury that is removed, the stronger the filling. The process ofexpelling mercury is known as drying. At the present time, drying isaccomplished by placing the amalgam in a small cloth pouch, and thepouch is squeezed and rolled between the thumb and forefinger or betweensimple pliers until mercury has been expelled from the amalgam in anamount consistent with the efiiciency of the methods employed. Thefinger-pressure method is tiresome and labo-v rious. The plier methodproduces only a static pressure and is therefore relatively inetficient.According to the present invention, a tool is designed to mechanicallyexpel mercury from the amalgam more efiiciently and thoroughly by meansof a kneading action or the like, specifically employing spring-loadedlevers for actuating a kneading member or roller against a shoe oranvil, the cloth pouch containing the amalgamknown as a dentalclothbeing received between the roller and shoe. The tool difiers from asimple pair of pliers in that the pressure applied to the roller orequivalent kneading member is dynamic rather than static and the springloading enables rolling or kneading in opposite directions in responseto alternate application and release of force to the actuating members,which members are, in a simple and preferred case, handles capable ofbeing gripped in one hand of the user.

It is a principal object of the invention to provide such tool in asimple and inexpensive form, and one that has relatively few movingparts so that it has the characteristic of long life and efliciency. Itis an important object of the invention to construct a tool that willplay an important role in the production of fillings of substantiallyhigher quality because of the ability of the tool to expel a higherpercentage of mercury than is possible by previously known methods. Astill further important feature of the invention resides in thearrangement of the linkage or lever means in conjunction with a springso that movement of the roller or kneading member against the shoe oranvil is accompanied by a progressively increasing pressure of theroller in one direction and conversely a decreasing pressure as theroller moves in the opposite direction. When this principle is utilizedin a plier-like instrument, the alternate application and relaxation ofmanual force to the handle will cause the roller Patented Aug. 28, 1956to roll or rock back and forth to impart a kneading action thereto whichis instrumental in expelling the maximum percentage of mercury from theamalgam. Another object of the invention is to provide the shoe or anvilwith a roughened area to constitute anti-skid means for preventingdisplacement of the amalgam while it is subjected to the squeezing orkneading action.

The foregoing and other important objects and desirable featuresinherent in and encompassed by the invention will become apparent tothose versed in the art as a preferred embodiment of the invention isfully disclosed in the following detailed description and accompanyingsheet of drawings in which Fig. 1 is a perspective view of the tool orappliance.

Fig. 2 is a fragmentary sectional view, as seen substantially along theline 2-2 of Fig. l, and showing the roller or kneading member in oneposition.

Fig. 3 is a transverse sectional view as seen substantially along theline 3--3 of Fig. 2.

Fig. 4 is a sectional view similar to Fig. 2 but showing the parts indiflerent positions.

Reference will be had first to Fig. 1 for an over-all explanation of thedevice. As seen in that figure, the tool or device comprises first andsecond elongated elements, designated generally by the numerals 10 and12 respectively. The element 10 is of such nature as to inciudeintegrally therewith an upper handle or force-receiving means 14 and alower jaw or arm 16 having an upper surface 18 that establishes a rampor track means. The elements 19 and 12 are crossed and are pivotallyinterconnected intermediate their ends as by pivot means including apivot pin 20 so that the element 12 includes a lower handle orforce-receiving means 22 disposed below the handle 14 and an upper armor jaw 24 disposed above the lower jaw or track 16.

Here, as well as in the claims, reference to the tool as having upper,lower, etc. parts is solely for convenience and is not designed toimpart any limitations into the spirit of the invention.

In the preferred embodiment of the invention illustrated, thearrangement of the elements 10 and 12 in crossed and pivotallyinterconnected form provides generally a plier association of the parts,so that squeezing of the handles 14 and 22 together causes the jaws orarms 16 and 24 to move together. Conversely, when the handles 14 and 22are spread apart, the jaws 16 and 24 move apart. The upper arm or jaw 24has a terminal end portion 26 that naturally moves in an are about thepivot pin 20 as it travels alternately toward and away from the track 18on the lower jaw or shoe 16. A link or lever 28 has an upper end 30pivotally connected to the terminal end 26 of the upper arm or jaw 24 bymeans of a pivot pin 32, the axis of which is parallel to the pivot orfulcrum axis 20. The lever 30 has a bifurcated lower end 34 between thefurcations of which is disposed a kneading or rocking member in the formof a roller 36. This roller preferably comprises a small sealed ballbearing having inner and outer races and journaled in the lower end 34of the link 28 by means of a shaft or pin 38 that establishes a rollingaxis parallel to the axes at 20 and 32. The link 28 .and roller 36 maybe said to constitute movable kneading or roller means carried by thesupport established by the upper arm or jaw 24. Intermediate its ends,the link or lever 28 has an apertured web portion 40 (Figs. 2, 3, and 4)into which is hooked one end 42 of biasing or energy-storing means, herein the form of a coiled tension spring 44, the other hooked end 46 ofwhich is connected to at least one of the elements 10 or 12 by means ofbeing hooked about the fulcrum or pivot pin 20.

Because of the plier form of the tool, the handles 14 and 22 are at oneside of the pivot axis 20 and are respectively above and below ahorizontal plane, for example, passed through that axis. Likewise, thejaws or arms 16 and 24 are at the other side of the pivot axls and arerespectively above and below such plane. The track 18 provided on thepaw or arm 16 is here shown as being in the form of a ramp or slope thatis directed downwardly and away from the pivot or fulcrum axis 20 tion,the spring 44 is stretched or additionally loaded and the energy storedtherein serves not only to improve the kneading action but to return theroller to its initial position. Consequently, the upper arm or support24 and the link or lever 28 comprise first and second levers in a linkmeans capable of imparting a rocking or kneading action to the roller 36in response to forces applied to and released from the force-receivingmeans comprising the handles 14 and 22. In the case of a manual tool, asillustrated, release of pressure or force on the handles is accompaniedby return of the roller 36 to its initial position, the spring 44serving at the same time to open the handles so that they may be againsqueezed together. Consequently, alternately squeezing and releasing thehandles causes the roller or pressure member 36 to rock or roll back andforth along the inclined shoe or ramp provided by the track 18.

The motion resulting from operation as just described is used to expelmercury and the like from amalgam received by the track or shoe 18. Aspreviously stated, it is conventional to utilize what is known as adental cloth for containing the amalgam. In the profession, such dentalcloth is approximately three inches in diameter and is placed in thepalm of the hand and a pellet of amalgam is placed in the center of thecloth. The cloth is then gathered together in pouch form and theoperator holds the loose ends of this pouch in his left hand and graspsthe handles 14 and 22 of the tool in his right hand (or vice versa if heso desires). Such pouch is not shown in detail in the drawings, since itis conventional and its use in the finger-pressure or plier method iswell known. However, for purposes of illushating the present invention,the pellet-containing portion of the pouch is designated by the letter Pand is shown in dotted lines in Figs. 2 and 4. In Fig. 4 the pouch hasbeen flattened as part of the kneading or rocking process.

As shown in Fig. 1, the upper surface of the anvil, track or shoe has aportion of its area roughened, as by being lightly knurled, as at 48, toprovide what may be called anti-skid means for preventing displacementof the amalgam-containing pouch.

It will be apparent from the foregoing description that the tool ordevice, as reduced to its substantially simplest form in the presentdisclosure, may be easily operated by manual pressure alternatelyapplied to and released from the handles 14 and 22. Force applied to thehandles causes the link 28 and roller 36 to be driven forwardly oroutwardly over the sloping track or ramp, whereupon the roller 36 rocksor rolls over the amalgam and the spring 44 is stretched, which isrepresented sub stantially by the change in positions of the partsbetween Figs. 2 and 4. Release of pressure or force on the handles 14and 22 allows the spring to retract the pressure or kneading meanscomprising the link 28 and roller 36 for rocking or rolling the roller36 in the opposite direction. Thus, not only is a downward pressureapplied to the kneading means but a motion is transmitted A thereto thatcauses it to rock or roll in one direction with a progressivelyincreasing dynamic pressure as opposed to a static pressure. The energystored in the spring produces a dynamic force as the roller 36 is drawnback uphill when pressure on the handles 14 and 22 is relaxed. Althoughthe ramp or track 18 is shown as being a curve concave as respects thepivotal connection 32, it may be straight or any other shape. Fig. 3shows that the track 18, as viewed from the end or in transversesection, is fiat; although, the shape could vary according to individualdesires, as could the shape of the roller 36 to correspond with theselected shape of the track 18. Based on present experiences, the track18 is a relatively long gentle curve arranged in progressivelyincreasing spaced relation to the terminal end portion 26 of the arm orsupport 24. Stated broadly, the invention appears to reside in the pairof opposed jaw-like elements 7 interconnected for relative movementtoward and away from each other, together with the rocking or pressuremember interposed therebetween and arranged to cooperate with one of thejaw elements to knead or roll over the amalgam carried by that one jaw,including force-transmitting means connected between the rolling orpressure means and one of theelement-s for causing the roller orpressure means to roll back and forth in response to movement of theelements relative to each other, thus producing a dynamic pressure, asaforesaid, as opposed to a static pressure resulting from simplysqueezing the amalgam.

Other features of the invention not specifically enumerated herein willundoubtedly occur to those versed in the art, as likewise will numerousmodifications and alterations in the preferred embodiment of theinvention, all of which may be achieved without departing from thespirit and scope of the invention.

What is claimed is:

1. A tool of the character described, comprising: first and secondelongated elements arranged in plier relationship and pivotallyinterconnected intermediate their ends on an axis transverse to theirlength to provide, on the first element, an upper handle and a loweranvil respectively at opposite sides of the pivot axis and, on thesecond element, a lower handle and an upper arm respectively at oppositesides of said pivot axis so that said lower handle is normally spacedbelow the upper handle and the arm is normally spaced above the anvil;said arm having a terminal end portion movable toward and away from theanvil on an are about the pivot axis when the handles are movedrespectively toward and away from each other; said anvil being of suchlength as to have a terminal end portion beyond said are and furtherhaving an upper surface sloping downwardly and away from the pivot axisin progressively increasing spaced relation to the terminal end portionof the arm; roller means arranged to roll along the anvil upper surfacebetween a starting position adjacent to the pivot axis and a secondposition adjacent to the terminal end portion of the anvil for rollingback and forth over a substance or object placed on the anvil uppersurface; lever means having an upper end rockably connected to theterminal end portion of the arm on an axis parallel to the pivot axisand a lower end connected to the roller means on the rolling axis of theroller means for moving the means from its starting position toward itssecond position when the handles are moved toward each other; andyielding means connected between the lever and one of the elements forbiasing the lever toward the pivot axis so as to bias the roller meansto its starting position. Y

Y 2. The invention defined in claim 1, in which: the upper anvil surfacehas at least a portion of its area roughened to provide anti-skid meansfor the substance or object placed thereon to be rolled over by theroller means.

3. The invention defined in claim 1, in which: the yielding meanscomprises a tension spring; the pivotal interconnection of the elementsincludes a pivot pin; and

the spring is connected at one end to the lever and at its other end tothe pivot pin.

4. The invention defined in clan'n 1, in which: the upper anvil surfaceis a relatively long gentle curve concave as respects the terminal endportion of the arm.

5. A tool of the character described comprising: first and secondelongated elements arranged in plier relationship and pivotallyinterconnected intermediate their ends on an axis transverse to theirlength to provide, on the first element, an upper handle and a loweranvil respectively at opposite sides of the pivot axis and, on thesecond element, a lower handle and an upper arm respectively at oppositesides of said pivot axis so that said lower handle is normally spacedbelow the upper handle and the arm is normally spaced above the anvil;said anvil having an upper surface running lengthwise below the arm andadapted to receive thereon a substance or object to be subjected topressure; said arm having a terminal end portion movable toward and awayfrom the anvil surface on an are about the pivot axis as the handles aremoved toward and away from each other; kneading means positioned betweenthe terminal end portion of the arm and the anvil upper surface tocontact such substance or object on said surface; and motiontransmittingmeans connecting the kneading means to the upper arm for applyingdownward pressure on the kneading means and simultaneously moving thekneading means back and forth along the anvil upper surface.

6. A dental tool for expelling mercury and the like from amalgam,comprising: anvil means having a surface on which the amalgam is placed;kneading means cooperative with the anvil surface to engage the amalgam;means connecting the kneading means to the anvil means for imparting arocking action to the kneading means; and means connected to thekneading means and to the anvil means for applying to the kneadingmeans, substantially simultaneously with said rocking action, a pressuredirected toward the anvil surface.

7. The invention defined in claim 6, in which: the anvil surface has atleast a portion of its area roughened to provide anti-skid means forrestraining the amalgam against displacement as it is kneaded.

8. A dental tool for expelling mercury and the like rom amalgam,comprising: anvil means having a surface on which the amalgam is placed;lever means fulcrurned on the anvil means and including force-receivingmeans to effect movement thereof toward and away from the anvil surface;kneading means cooperative \m'th the anvil surface to engage the amalgamon said surface; means interconnecting the lever means and the kneadingmeans for moving the kneading means back and forth over thesurface-carried amalgam in opposite directions of movement of the levermeans; and yielding means connected between the kneading means and theanvil means for biasing the kneading means into intimate contact withthe amalgam as said kneading means is moved back and forth as aforesaid.

9. A dental tool for expelling mercury and the like from amalgam,comprising: a pair of opposed jaw-like elements interconnected forrelative movement toward and away from each other, one of said elementshaving thereon and opposed to the other of said elements a surface forcarrying amalgam; rolling means interposed between the elements andarranged to engage the elementcarried amalgam; means respectively on theelements for moving them relatively toward and away from each other; andforce-transmitting means connected between the rolling means and one ofthe elements for causing the rolling means to roll back and forth overthe element-carried amalgam in response to movement of the elementsrelative to each other.

10. A dental tool for expelling mercury and the like from amalgam,comprising: a pair of elements interconnected for relative movement andincluding opposed handles for receiving manual force and opposed armsmovable alternately toward and away from each other in response to thealternate application and release of such manual force; means on one armfor carrying amalgam; a pressure member cooperative with said means andengageable with amalgam carried by said means; means connecting thepressure member to one of the elements for pressing said member towardthe amalgam-carrying means and simultaneously rocking said member in onedirection in response to force applied to the handles; andenergy-storing means connected to the pressure member and to one of theelements and loaded upon said rocking of the pressure member forpressing said member toward the amalgam-carrying means andsimultaneously rocking said member in the opposite direction uponrelease of force from the handles.

11. A dental tool for expelling mercury and the like from amalgam,comprising: a pair of elongated elements interconnected for relativemovement and including opposed handles for receiving manual force andopposed arms movable alternately toward and away from each other inresponse to the alternate application and release of such manual force;means on one arm for carrying amalgam including a track runninglengthwise of said one arm and opposed to the other arm; a rollercooperative with said track means and engageable with amalgam carriedthereby; means connecting the roller to one of the elements for pressingsaid roller toward the track means and simultaneously causing saidroller to roll in one direction in response to force applied to thehandles; and energy-storing means connected to the roller and to one ofthe elements and loaded upon said rocking of the pressure member forpressing said roller toward the track means and simultaneously causingthe roller to roll in the opposite direction upon release of force fromthe handles.

12. The invention defined in claim 11, in which: the track means has aroughened surface portion preventing displacement of the amalgam .as theroller is caused to roll back and forth.

13. A dental tool for expelling mercury from amal garn, comprising:anvil means having a surface adapted to receive amalgam thereon to besubjected to pressure; kneading means arranged proximate to the anvilmeans surface to contact such amalgam; and movable along said surface tosqueeze the amalgam; means connected respectively to the anvil means andto the kneading means for receiving force; and force-transmitting meansconnected to the force-receiving means and to the kneading means forapplying a progressively increasing force to the kneading means and thusto produce a dynamic kneading pressure on the amalgam.

14. A dental tool for expelling mercury from amalgam, comprising: anvilmeans having a surface adapted to receive amalgam thereon; pressuremeans cooperative with the anvil means to squeeze such amalgam againstthe anvil means; lever means interconnecting the anvil means and thepressure means for moving the two relatively, said lever means includinga first lever pivoted to the anvil means and a second lever pivoted tothe first lever and additionally pivoted to the pressure means; springmeans interconnecting the first and second levers and exerting aninitial force pressing the pressure means against the amalgam on theanvil means surface to apply an initial squeezing pressure thereon; andforcereceiving means connected to the lever means for moving the leversrelatively against the spring means to progressively increase the loadon the spring means and thereby to progressively increase the pressureapplied by the pressure means.

References Cited in the file of this patent UNITED STATES PATENTS770,162 Chase Sept. 13, 1904 1,262,621 Beacha-m Apr. 16, 1918 2,399,834Seltzer May 7, 1946

